1. Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
2. Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Syowa-ku, Nagoya City, Aichi, 466-8550, Japan
3. Department of Endoscopy, Nagoya University Hospital, Showa-ku, Nagoya, Japan